Switchgrass Lessens Soil Nitrate Loss Into Waterways

Tuesday, August 10 2010

By planting switchgrass and using certain agronomic practices, farmers can significantly reduce the amount of nitrogen and nitrates that leach into the soil, according to Iowa State University research.

Matt Helmers, associate professor of Agricultural and Biosystems Engineering, and Antonio Mallarino, professor of Agronomy, have been studying the amount of nitrates that pass through soil into tiling systems from several different types of crops and fertilizer treatments for the past three summers.

"One of the biggest things we found is that when alternative biomass sources like switchgrass are grown, even when they use fertilizer, we see dramatically lower nitrate concentrations (in the drainage water)," said Helmers.

The research compared fields that were planted with continuous corn while harvesting just the grain; continuous corn taking the grain and stover; and planting continuous corn taking all possible biomass from the fields. Half of those fields were treated with fertilizer and the other half with manure.